Protective device for electric lamp assemblies



June 24, 1941.

I ,Elin

c.. v. LINDBLOOM -l-:r A L 2,246,945 PROTECTIVE DEVICE FOR ELECTRIC LAMPASSEMBLIES Filed July 29, 1938 Patented .lune 24, 1941 UNTE s air andereIROTECTIVE DEVICE FOR ELECTRIC LAB@ ASSEMBLIES Delaware Application July29, 1938, Serial No. 221,892

(Cl. 24d-11.3)

'l Claims.

This invention relates to a safety device for electric lamp assemblies.vMore particularly the invention relates to a device, including aY lampinA an electric circuit, which provides a means for automaticallybreaking the electric circuit when the lamp is ruptured, so as to exposethe lament therein, such means also providing against accidentalre-establishment of the circuit prior to the insertion of a new lamp.Speciiically, the invention relates to a device of such nature,including means to crush the lamp lament operable upon rupture of thelamp, and to interrupt the flow of current normally passing through thelamp circuit. It is an object of this invention to provide a device ofsuch nature that, when used in an explosive or inflammable atmosphere,it shallV be substantially explosionproof.

These purposes, and other objects of the invention, not specificallyenumerated, may be fully understood from the speciiications hereinafterset forth, when read in conjunction with the accompanying drawing, inwhich:

Fig. 1 is a side elevation showing the support, casing and exteriorportion of the operating mechanism in one form of the invention.

Fig. 2 is-a plan view'of the structure shownl in Fig. 1.

Fig. 3 is an enlarged View, in verticalsection, of the device accordingto Fig. 1.

Fig. 4 is an enlarged view, in vertical section of a portionof thedevice according to Fig. l-

showing the relation of parts upon rupture of the lamp.

Fig. 5 is a section View taken on the line 5--55 of Fig. 3.

Fig. 6 is aside elevation of another form'of the invention adapted foruse in connection with a conventional lighting system; Y

Fig. 7 is a detailed view of an alternate form of snuiier for the lampfilament.Y

Referring to the drawing, and in particular to Figures 1 to 5 inclusive,there is'shown, as illustrative ofthe invention, a device suitable foruse in connection with a signal lantern. A bracket. or supporting memberI is provided with a boss 2r on its upper surface,l the boss having aneck portion 3 of less diameter forming a shoulder 4. A cylindricalshell or casing 5, the lower edge of which is flanged as at 5, istightly fitted overthe neck 3 with the 'ange 6 abutting against thelshoulder 4. The boss 2 is provided with centrally disposedlvertical'passa'geway "I and an eccentrically disposed'vertical guideway8; both and the lamp socket I'i.

of which open into the casing 5 when that member isapplied.

In the upper end of the casing 5, there is a central aperture 9 which isadaptedl to receive a sleeve I0. The sleeve II) is preferably formed ofa compressible and deformable substance such as rubber to provide a'fludand vapor-tight joint between the edges of the aperture 9 anda lampsocket I'I disposed within the sleeve lil. This sleeve extends upwardlybeyond the aperture for a short distance and engages; the sidewalls ofthe lamp I2 threaded into the socket II. Also in the upper wall of the'casing 5, an eccentrically disposed aperture I3 is provided forarrangement in spaced correlation with the guideway 8.

A bolt and' nut I4 extending through an opening in a wall of the casingadjustably secures a bracket I5 to said wall, the bracket I5' having aslotted portion It. engaged by the nut, and an annular disc shapedportion Il disposed at they upper end of the slotted portion I insubstantially vright angular relation thereto, and supportedtherebycentrally of the casing.

Above the disc II` are disposed an annular insulating washer I8, anannular contact disc I9 Below the disc Il are disposed an annularinsulating washer 2l) and a contact'disc 2l. A rivet 22' passing throughthe bottom Wall of the socket II, without contact therewith', andinsulated therefrom by the Washer 23, extends downwardly through thecenter openings of the members I9, I8, Il, 2t and 2i and serves torigidly connect these members with the socket II with the disc Il,carried by the bracket I5, supporting the assembly. The rivet 22 is ofcopper or another material which will readily conduct an electriccurrent. The central openings of the discs Il and I9 are large enough topreventcontact with the sides ofthe rivet 22. A wire 23a is secured tothe Contact dise I9 as by a'tab 24 on the disc, as shown in Fig'. Il.The wire extends downward in the casing and through the passageway l, toa source of -electric energy. The lamp I2 when. threaded into thesooketI I makes contact with the head of the rivet 22'.`

DisposedY in the aperture I3, a sleeve 25 carries a plunger rod 2S' inclose fitting slidable relation in the sleeve bore, the rod extendingdown- Wardly through sleeve and casing, with the lower end of the rodslidably engaging the inner wall of the guideway 3. The upper end of therod 25 is bent at 2T to forman angularly extending arm 28which carriesamember 29 adapted to engage the curved, upper surface of the lamp I2.The

member 29 may be formed by deformation of the end portion of the arm 28into a substantially circular shape, with the end 30 extendingdiametrically across the portion thus formed.

Within the casing 5, a rectangular or a round block 3|, ofnon-conductive material such as Bakelite, is secured to the rod 26 at apoint intermediate its length, and extends outwardly from the rod in thesame direction with and substantially parallel to the arm 28. The block3| may be rigidly aliixed to the rod 26, or may be freely supportedthereon as by the fixed collar 3Ia. A spring member 32 is disposed onthe rod 26 with its upper end abutting against the sleeve 25, and itslower end against the member 3|. The portion of the member 3| whichextends beyond the rod is :disposed beneath the disc 2| supported by thebracket l5, and having a passage 33 in its outer end, this member 3|provides a sleeve for a resiliently mounted contact plunger 34.

The upper end of the plunger 34 has a head 35 which is adapted to makecontact with the disc 2|. A coiled spring member 36 surrounds theplunger 34 abutting at one end against the head 35, and at the otheragainst the block 3|. To the lower end of the plunger 34, extendingbeyond the block, wire 3l is secured, and extends downwardly from thecasing through the passageway to a source of electric energy, and withthe wire 24, completing the lamp circuit. By use of this resilientmounting, adjustment of the socket assembly is facilitated, the positionof the contact plunger 34 being variable by the action of spring 36. Ifdesired, a manual switch, Y

an automatic blinker switch, or both, may be introduced into the circuitin any conventional manner.

In the form of the invention illustrated by Fig. 6, an adapter for aconventional lamp socket, the general construction involved is identicalwith that previously described in connection with Figs. 1 to 5inclusive, with the exception that it may be necessary to provide forangular entry of the rod 26a into the casing 5a in order to avoidconta-ct of the rod with the curved side of the lamp |2a in the socketIla. The casing 5a while of somewhat diiferent form and provided with athreaded plug connection 38 contains structural elements which aresubstantially similar to those shown in the casing as illustrated inFigs. 3 and 4.

In Fig. '7, an alternate form for the member 29, of the previousfigures, is shown, which form is preferred for use with the adaptershown in Fig. 6. According to this modification, the member 29a carriesan extensible spring member 39 having a bar 40 disposed diametrically ofits lower end. The spring 39 is normally held compressed within themember 29a when that member is supported on the upper end of the lamp|2a.

As has been stated, the device set forth above is designed to permit theuse of an electric lamp in the presence of inflammable vapors, or anyother atmosphere of an explosive or combustible nature, withoutsubstantial danger of ignition should the lamp be broken, and thefilament therein exposed. When a device of the nature set forth is notused, the filament will Hash or glow until fused and destroyed, andduring such period, may ignite any inflammable material which may bepresent. This device operates automatically, upon rupture of the lamp,to both break the circuit to the lamp socket and to simultaneouslyfracture the filament of the lamp, snuftlng out any residual glow in theexposed filament, and aiding in the dissipation of heat in the filament.

Comparable devices have been previously disclosed for accomplishingsimilar objectives, but in general, they have been dependent uponmovement of the lamp or lamp socket to both break the electrical circuitand to fracture the lamp filament. Furthermore, previous devices of thisnature have been rendered unserviceable by the interference with theiroperation of corrosion, moisture, dirt and glass particles from thefractured lamp. Few, if any, of the devices previously disclosedprovided for adjustment of the lamp assembly for the purpose of focusingor otherwise.

The assembly as shown in Figs. l, 2, 3 and 6, is illustrated as itappears in condition for normal operation, and with the protectivedevice in position and ready to break the electrical circuit if the lampshould be fractured. In this position of the spring 32, .acting againstthe block 3| attached to the rod 26, is urging the rod downward so thatthe member 29, carried by the rod, presses against the top of the lamp.As long as this condition exists, the head 35 of the plunger 34 ispressed upward by means of spring36, into contact with the contact disc2| which, through the rivet 22, is in electrical contact with the lampbase. The outer shell of the lamp I2 is in contact with the socketmember Il and this member in turn is in electrical contact with the disc|9 to the tab 24 to which one end of the wire 23a is connected. Thus thecircuit is completed through the lamp.

If at any time the bulb of the lamp should break there will be nothingto hold the member 29 and the rod 26, to which it is connected, in theraised position shown in Figs. l, 3 and 6, so that the rod 26 will beforced down instantly by the action of the spring 32. As the rod 26moves downward in the sleeve 25, it does so very rapidly andsufficiently far to move the head 35 of the plunger 34 entirely awayfrom the contact member 2| and automatically opens or breaks the circuitthrough the filament of the lamp. This action takes place so quicklywhenever the bulb breaks, that the exposed filament will not flash' norglow. The portion 3D of the member 29 destroys the lamp lament, breakingit into small pieces from which residual heat is rapidlyv and safelydissipated. The circuit cannot be re-established accidently, as apositive action rais ing of the rod 2li-is required to do so. viouslythe rod will not be raised except upon insertion of a new lamp in thesocket The rod 26 together with its arm 2 are adapted to be turnedbecause the rod is revolvable in the sleeve 25 as well as in the block3| To replace the destroyed lamp, it is only necessary to grasp the arm28 and rotate the rod 26 to swing the cross arm away from the lampsocket. Then the broken lamp may be unscrewed from the socket and a newlamp may be screwed into it so that the unbroken bulb of the new lampprojects above the casing. The cross arm 28 may then be grasped and thisarm, together with the rod 26 may be raised by pulling against thetension of the spring 32 and 36 until the arm is level with or above thetop of the bulb, whereupon the arm may be turned until the member 29 isin line with and rests upon the top of the bulb, at which time thecondition shown in Figs. 1, 2, 3 and 6 will be restored.

When the rod 25 is thus lifted, the block 3i moves with it andthe hea-d35 of the plunger 34 is pressed against the under side of the contactmember 2| so that the circuit is again completed through the lamp. Whilethe spring 32 in itself would permit the plunger 3d to be held incontact with the contact member 2l, it is preferred to provide thespring Se for pressing the plunger upward in the manner described above.

From the above it will be apparent that we are able to use an ordinaryor standard type of lamp and to screw it firmly in its socket in thesame manner that lamps are applied to ordinary or standard sockets. Itwill also be apparent that the lamp itself is not moved by the circuitbreaking device when the bulb breaks and as there is no movement of thebulb there is no possibility of dirt or fragments of the broken bulbgetting between the base of the lamp and its sock-et and interferingwith the movement of the lamp. As a matter of fact, no fragments orglass can enter between the base of the lamp and its socket because ofthe rubber sleeve I3.

The vertically moving rod 25 can be moved faster and its movement ismore dependable than where the lamp is bodily moved to open the circuit.

In Fig. 6 we have shown the vdevice adapted to be used for protectingany type of yelectric lamp, that is to say, it is not necessarilyemployed in connection with a signal lamp but it may be used to protectthe circuit of the ordinary lighting lamps in factories, oil works, etc.where explosive or inflammable vapors or gases may exist. In this formthe device is made as an adapter. The shell a preferably of cylindricalform, has a tubular extension 38 at one end, adapted to be screwed intoany ordinary lamp socket in any lighting circuit. At the other end ofthe casing there is a socket lla to receive the base of an ordinaryelectric lamp la. The adapter may be screwed into any lamp socket andthe lamp may be screwed into the other end of the adapter after whichthe rod 2M and the cross arm may be pulled out and the rod turned untilthe member 23a on the cross arm presses down on the tcp of the bulb.

The device will then operate in connection with this bulb in the samemanner and for the same purpose as the device shown in Figs. 1 to 5inclusive. With this type of adapter all ordinary lamps may be protectedand it is not necessary either to provide a special socket for theadapter nor to provide a special type of lamp. The rod 23a in thisdevice is preferably disposed at an angle to the axis of the shell inorder to pass over the larger diameter of the bulb.

Although, for the purpose of illustration a preferred form of theinvention has been set forth above, it is obvious that variousalterations and alternative arrangements may be made therein withoutsubstantially departing from the inventive concept. And it is notintended that the invention be limited by such illustrative disclosure,but only by the appended claims in which it is intended to claim allnovelty inherent in the invention.

We claim:

1. In combination, an incandescent lamp socket, a housing for saidsocket, a lamp bulb in the socket having a lament supported therein, aquenching element engaging the bulb, and moveable in a path extendingthrough the bulb lament, a support member integral with said element,extending into the housing adjacent the socket, disposed for movementsubstantially longitudinally therein, and resilient means within thehousing engaging said member -to movev the quenching element through thef'llament upon fracture of the bulb.

` 2.. `In a device according toclaim 1, a quenching element, comprisinga spiral coil element, and an end portion on said element extendingdiametrically across the inner circle formed by the spiral coil.

3. In a device according to claim 1, a quenching element, comprising ahelical coil spring element dependent from said support member at thegreatest diameter of said coil, said spring element being normallycompressed in nested relation, by engagement with a lamp bulb.

4. In combination, an incandescent lamp socket, a housing for saidsocket, a lamp bulb in the socket having a filament supported therein, aquenching element engaging the bulb, and moveable in a path extendingthrough said lament, a support member integral with said element,extending into the housing adjacent the socket, disposed for movementsubstantially longitudinally therein, an electric circuit through saidlamp bulb and socket, means resiliently carried by said support memberwithin the housing to make and break said circuit, and resilient meanswithin the housing engaging said support member and housing to move thequenching element through the filament, and break the circuit uponfracture of the bulb.

5. A device of the character described, comprising in combination, ahousing, a lamp socket adjustably supported in said housing, extendingoutward therethrough, a lamp bulb mounted in removably fixed relation insaid socket, an electric circuit through said bulb and socket, and meansdispose-d within the housing to make and break the circuit consisting ofa rotatable rod extending outward through the housing adjacent thesocket, an arm on the outer end of said rod to engage the bulb, asupport element intermediate the rod within the housing, a contactelement in the circuit resiliently mounted in said support, and springmeans between the support and housing to hold the rod arm in contactwith the bulb, and move the rod and support substantially longitudinallyof the housing upon fracture of the bulb to break said circuit'.

6. A device of the character described, including a socket adapted toreceive and hold an electric lamp, a member mounted to slide and havingmeans to engage the bulb of a lamp in said socket, spring means foroperating said sliding member to cause it to press on the lamp bulb andto move if the bulb breaks, a member carried by said sliding member, aplunger carried by said members, a spring for moving said plungerrelatively to said sliding member, a contact member included in circuitwith said lamp and in contact with which said plunger is held by itsspring, the plunger being adapted to be moved from said contact memberwhen said sliding member is moved by its spring upon the breaking ofsaid bulb.

'7. A device of the character described, including a socket adapted toreceive and hold an electric lamp, a member mounted to slide and havingmeans to engage the bulb of a lamp in said socket, spring means formoving said sliding member in one direction to cause it to press on thelamp bulb and to move if the bulb breaks, member carried by said slidingmemthe plunger being adapted to be moved from ber, a plunger carried bysaid members, a spring said Contact member when said sliding member formoving said plunger in the opposite direcis moved by its spring upon thebreaking of tion to the movement of said sliding member said bulb.

by its spring, a contact member included in an 5 CHARLES V. LINDBLOOM.electric circuit with said lamp and in Contact HAROLD B. HENDRIX.

with which said plunger is held by its spring,

